Test method for assessing irritation of skin

ABSTRACT

Test methods for assessing irritation of portions of skin and/or assessing inhibition and/or reduction of such irritation are provided.

FIELD OF THE INVENTION

The present invention relates to test methods for assessing irritationof portions of skin and/or assessing inhibition and/or reduction of suchirritation. More particularly, the present invention relates to testmethods for assessing the inhibition and/or reduction of irritation ofskin from fibrous structures, especially lotion-containing fibrousstructures that come in contact with such irritated skin.

BACKGROUND OF THE INVENTION

Cold and allergy sufferers often develop irritation around the nostrilsas a result of repeated and frequent rubbing of the skin site withfacial tissues. This irritation is a combination of the inherentirritant properties of the tissue components (chemical irritation), andmechanical irritation from friction.

Over the years, formulators have tried to assess the irritation and/orthe inhibition and/or reduction of such irritation by various products,such as topical lotions and creams.

A prior art test method comprised compromising a portion of skin with achemical irritant and then directly applying a lotion to the irritatedportion of skin.

Another prior art test method comprised compromising a portion of skinby tape stripping the portion of skin and then contacting the irritatedportion of skin with a facial tissue in a one-wipe pass over theirritated portion of skin.

However, none of the existing prior art test methods are suitable forassessing skin irritation of cold sufferers because the irritationaround one's nostrils during a cold is a combination of effects,including the inherent irritant properties of the tissue components(i.e., chemical irritants), and mechanical irritation from frictionresulting from frequent and repeated rubbing of the irritated skin witha tissue.

Accordingly, there is a need for a test method that is capable ofassessing the skin irritation present on the skin of a cold sufferer.

SUMMARY OF THE INVENTION

The present invention fulfills the need identified above by providing atest method that is capable of assessing irritation of portions of skinand/or assessing inhibition and/or reduction of such irritation.

In one example of the present invention, a method for assessingirritation of skin, the method comprising the steps of:

a. irritating a portion of skin by a first mode;

b. irritating the portion of skin by a second mode different from thefirst mode, wherein the second mode comprises rubbing a substrate on theportion of skin; and

c. assessing erythema and/or dryness of the portion of the skin; and

d. optionally, assessing objective instrumental measurements, isprovided.

In another example of the present invention, a method for assessingirritation of skin, the method comprising the steps of:

a. irritating a portion of skin by a first mode comprising contact theportion of skin with a chemical irritant;

b. irritating the portion of skin by a second mode different from thefirst mode; and

c. assessing erythema and/or dryness of the portion of the skin; and

d. optionally, assessing objective instrumental measurements, isprovided.

Accordingly, the present invention provides a test method that iscapable of assessing irritation of portions of skin and/or assessinginhibition and/or reduction of such irritation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a bar chart showing dryness data from two substrates testedaccording to one example of the present invention;

FIG. 1B is a bar chart showing erythema data from two substrates testedaccording to one example of the present invention;

FIG. 2A is a bar chart showing dryness data from two substrates testedaccording to one example of the present invention;

FIG. 2B is a bar chart showing erythema data from two substrates testedaccording to one example of the present invention;

FIG. 3A is a bar chart showing dryness data from two substrates testedaccording to one example of the present invention; and

FIG. 3B is a bar chart showing erythema data from two substrates testedaccording to one example of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

“Mode” as used herein means a specific way of doing something. In thepresent case, it is a specific way out of numerous ways of irritating aportion of skin.

“Irritation” or “irritate” or “irritating” as used herein means that aportion of skin exhibits signs of chafing and/or inflammation and/orabrasion.

“Chemical irritation” as used herein means that a chemical agentcontacts a portion of skin such that it irritates the portion of skin.

“Physical irritation” as used herein means that a non-chemical agentcontacts a portion of skin in such a way to cause irritation of theportion of skin. Nonlimiting examples of sources of physical irritationinclude tape stripping the portion of skin, rubbing a substrate acrossthe portion of skin, rubbing a hand across the portion of skin,occluding the skin from an external environment, and subjecting theportion of skin to excessive wind.

“Mechanical irritation” as used herein means a physical irritation thatis caused by a physical object contacting the portion of skin to causeirritation.

“Frictional irritation” as used herein means a mechanical irritationthat is caused by a physical object, such as a substrate, repeatedlycontacting the portion of skin in a rubbing manner to cause irritation.

“Substrate” as used herein means a physical object upon which and/orwithin which one or more additive ingredients may be deposited.

“Fibrous structure” as used herein means a substrate that comprises oneor more fibers, natural and/or synthetic. Nonlimiting examples offibrous structures include feminine care products (pads, tampons,wipes), adult incontinence products, sanitary tissue products (facialtissue, toilet tissue, paper towels, wipes), baby care products(diapers, wipes), fabrics and home care products (cleaning wipes,dusting wipes).

“Sanitary tissue products” as used herein means facial tissue, toilettissue, paper towels and wipes.

“Erythema” as used herein means visually recognizable redness of theskin.

“Dryness” as used herein means visually recognizable powderiness orcracking of the skin.

Test Method

The test method of the present invention comprises a method forassessing irritation of skin.

The method comprises the steps of:

a. irritating a portion of skin by a first mode;

b. irritating the portion of skin by a second mode different from thefirst mode, wherein the second mode comprises rubbing a substrate on theportion of skin; and

c. assessing erythema and/or dryness of the portion of the skin; and

d. assessing objective instrumental measurements.

The step of irritating a portion of skin may comprise chemicallyirritating a portion of skin and/or physically irritating a portion ofskin.

Nonlimiting examples of portions of skin suitable for use in the presentinvention include forearm skin. In one example, the portion of skin isthe volar and/or flexor surface portion of the forearm. Two, three ormore portions of skin on one forearm may be subjected to the test methodof the present invention. The portions of skin may be any size. In oneexample, the size of the portion of skin is 4 cm×4 cm. Portions of skinmay be 4 cm apart from the other on the forearm.

A nonlimiting example of chemical irritation of a portion of skinincludes contacting the portion of skin with a skin irritant agent.Nonlimiting examples of suitable skin irritants include sodium laurylsulfate and sodium laureth sulfate.

A nonlimiting example of physical irritation of a portion of skinincludes tape stripping the portion of skin. In other words, applying apiece of tape to the portion of skin and then removing the tape suchthat the portion of skin becomes irritated.

Another nonlimiting example of physical irritation of a portion of skinincludes occluding the portion of skin. One way of occluding comprisesplacing a patch, such as a Webril® patch, commercially available fromProfessional Medical Products Company) over the portion of skin. Tape,such as an occlusive, hypoallergenic tape, such as Blenderm® tape,commercially available from 3M Company, may be used to cover the patchand hold the patch in place on the portion of skin. The patch may alsocomprise a skin irritant to facilitate irritation of the skin.

The rubbing of the substrate across the portion of skin can occur in aback and forth manner, a circular manner and/or a multi-directional (twoor more) manner and/or in a unidirectional manner, if the skin has beenchemically irritated prior to rubbing.

The substrate may be a fibrous structure.

The fibrous structure may be embossed and/or may be pattern-densified.

The fibrous structure may be creped or uncreped.

The fibrous structure may comprise a nonwoven web.

The fibrous structure may comprise a cellulosic fiber containing web.

In one example, the substrate is a single- or multi-ply sanitary tissueproduct, specifically a sanitary tissue product comprising an additiveingredient, such as a lotion.

The additive ingredient may be present on a surface of the substrate.When the additive ingredient is a lotion and it is present on thesurface of the substrate, a silicone may be present directly on thesubstrate and then the lotion may be present on top of the silicone. Thelotion may be a transferable lotion, a minimally transferable lotion ora non-transferable lotion.

Nonlimiting examples of additive ingredients include chemical softeningagents, dyes, colorants, surfactants, absorbents, permanent wet strengthagents, temporary wet strength agents, antiviral agents, oils,nanotechnology agents, lotion compositions, skin benefits agents, skinhealants, perfumes, especially long lasting and/or enduring perfumes,antibacterial agents, botanical agents, disinfectants, pharmaceuticalagents, film formers, deodorants, opacifiers, astringents, solvents,cooling sensate agents such as camphor, thymol and menthol, andpreservatives.

Nonlimiting examples of suitable chemical softening agents includesilicones, quaternary ammonium compounds, petrolatum, oils, and mixturesthereof.

Nonlimiting examples of silicones include aminosilicones and/or cationicsilicones.

In another example of the present invention, the method comprises thesteps of:

a. irritating a portion of skin by a first mode comprising contact theportion of skin with a chemical irritant;

b. irritating the portion of skin by a second mode different from thefirst mode;

c. assessing erythema and/or dryness of the portion of the skin; and

d. assessing objective instrumental measurements.

The methods of the present invention may include pretreatment stepsprior to irritating a portion of skin. Nonlimiting examples ofpretreatment steps include contacting a portion of skin with an additiveingredient, such as a lotion.

Assessing erythema and/or dryness of the portion of the skin can be donevisually. For example, a panel of experts can visually grade erythemaand/or dryness of a portion of skin. Suitable grading scales for botherythema and dryness are set out below in Tables 1 and 2, respectively.

TABLE 1 Erythema Grading Scale 0 No apparent cutaneous involvement 0.5Faint, barely perceptible erythema or slight dryness 1 Faint, butdefinite erythema, definite dryness 1.5 Well-defined erythema or fainterythema with definite dryness 2 Moderate erythema; may have papules ordeep fissures 2.5 Moderate erythema with barely perceptible edema; mayhave a few papules 3 Severe erythema (beet redness); may havegeneralized papules 3.5 Moderate-to-severe erythema with moderate edema4 Moderate-to-severed erythema and/or extending edema, may havegeneralized vesicles or eschar formations

TABLE 2 Dryness Grading Scale 0 None 1 Patchy, slight powderiness withsmall scales 2 General, slight powderiness with small lifting scales 3General, moderate powderiness with cracking and scales 4 General, heavypowderiness with cracking and lifting scales 5 Heavy cracking (possiblybleeding) and lifting scales 6 Severe cracking, with bleeding andsloughing of large scales

The step of assessing erythema and/or dryness by objective instrumentalmeasurements may include evaluating the portion of skin with atransepidermal water loss instrument, commercially available from CortexTechnology, Denmark under the tradename TEWL, DermaLab® Evaporimeter.Participants may be conditioned in a temperature and humidity controlledroom (73° F.±4° F. (about 23° C.±2.2° C.) and a relative humidity of50%±10%) for approximately 20 minutes.

Even though the description above of this test method is directed toassessing irritation of skin, one can also measure lotion or additive(such as perfumes, preservatives, antiviral, antibacterial, skinhealants, skin benefit agents, non-active agents) transfer during thistest method by determining the amount of lotion or other additive thattransfers from the substrate to the skin.

Additive Ingredients

Nonlimiting examples of additive ingredients that may be incorporated onand/or in the substrate include surface treating compositions including,but not limited to, nanotechnology agents, lotion compositions, skinbenefit agents, perfumes, especially long lasting and/or enduringperfumes, antibacterial agents, antiviral agents, botanical agents,disinfectants, pharmaceutical agents, film formers, deodorants,opacifiers, astringents, solvents, cooling sensate agents, such ascamphor, thymol and menthol.

A surface treating composition, for purposes of the present invention,is a composition that improves the tactile sensation of a surface of asubstrate, such as a fibrous structure, perceived by a user whom holdsthe substrate and rubs it across the user's skin. Such tactileperceivable softness can be characterized by, but is not limited to,friction, flexibility, and smoothness, as well as subjectivedescriptors, such as a feeling like lubricious, velvet, silk or flannel.

The surface treating composition may or may not be transferable.Typically, it is substantially non-transferable.

The surface treating composition may increase or decrease the surfacefriction of the surface of the fibrous structure, especially the usercontacting surface of the fibrous structure. Typically, the surfacetreating composition will reduce the surface friction of the surface ofthe fibrous structure compared to a surface of the fibrous structurewithout such surface treating composition.

Nonlimiting examples of suitable surface treating agents can be selectedfrom the group consisting of: polymers such as polyethylene andderivatives thereof, hydrocarbons, waxes, oils, silicones,organosilicones (oil compatible), quaternary ammonium compounds,fluorocarbons, substituted C₁₀–C₂₂ alkanes, substituted C₁₀–C₂₂ alkenes,in particular derivatives of fatty alcohols and fatty acids(such asfatty acid amides, fatty acid condensates and fatty alcoholcondensates), polyols, derivatives of polyols (such as esters andethers), sugar derivatives (such as ethers and esters), polyglycols(such as polyethyleneglycol) and mixtures thereof.

In one example, the surface treating composition of the presentinvention is a microemulsion and/or a macroemulsion of a surfacetreating agent (for example an aminofunctional polydimethylsiloxane,specifically an aminoethylaminopropyl polydimethylsiloxane) in water. Insuch an example, the concentration of the surface treating agent withinthe surface treating composition may be from about 3% to about 60%and/or from about 4% to about 50% and/or from about 5% to about 40%. Anonlimiting examples of such microemulsions are commercially availablefrom Wacker Chemie (MR1003, MR103, MR102). A nonlimiting example of sucha macroemulsion is commercially available from General ElectricSilicones (CM849).

Nonlimiting examples of suitable waxes may be selected from the groupconsisting of: paraffin, polyethylene waxes, beeswax and mixturesthereof.

Nonlimiting examples of suitable oils may be selected from the groupconsisting of: mineral oil, silicone oil, silicone gels, petrolatum andmixtures thereof.

Nonlimiting examples of suitable silicones may be selected from thegroup consisting of: polydimethylsiloxanes, aminosilicones, cationicsilicones, quaternary silicones, silicone betaines and mixtures thereof.

Nonlimiting examples of quaternary ammonium compounds suitable for usein the present invention include the well-known dialkyldimethylammoniumsalts such as ditallowdimethylammonium chloride,ditallowdimethylammonium methylsulfate, di(hydrogenatedtallow)dimethylammonium chloride. In one example, the surface treatingcomposition comprises di(hydrogenated tallow)dimethylammonium chloride,commercially available from Witco Chemical Company Inc. of Dublin, Ohioas Varisoft 137®.

Nonlimiting examples of ester-functional quaternary ammonium compoundshaving the structures named above and suitable for use in the presentinvention include the well-known diester dialkyl dimethyl ammonium saltssuch as diester ditallow dimethyl ammonium chloride, monoester ditallowdimethyl ammonium chloride, diester ditallow dimethyl ammonium methylsulfate, diester di(hydrogenated)tallow dimethyl ammonium methylsulfate, diester di(hydrogenated)tallow dimethyl ammonium chloride, andmixtures thereof. In one example, the surface treating compositioncomprises diester ditallow dimethyl ammonium chloride and/or diesterdi(hydrogenated)tallow dimethyl ammonium chloride, both commerciallyavailable from Witco Chemical Company Inc. of Dublin, Ohio under thetradename “ADOGEN SDMC”.

For purposes herein, nanotechnology agents are defined as particlesexhibiting average diameters of about 500 nm or less. In one example,particle size distributions of the nanotechnology agents in the presentinvention may fall anywhere within the range from about 2 nm to lessthan about 500 nm, alternatively from about 2 nm to less than about 100nm, and alternatively from about 2 nm to less than about 50 nm. Forexample, a layer synthetic silicate can have a mean particle size ofabout 25 nanometers while its particle size distribution can generallyvary between about 10 nm to about 40 nm. Alternatively, nanotechnologyagents can also include crystalline or amorphous particles with aparticle size from about 2 to about 100 nanometers, alternatively fromabout 2 to about 50 nanometers.

Inorganic nanotechnology agents generally exist as oxides, silicates,carbonates and hydroxides. Some layered clay minerals and inorganicmetal oxides can be examples of nanotechnology agents. The layered clayminerals suitable for use in the present invention include those in thegeological classes of the smectites, the kaolins, the illites, thechlorites, the attapulgites and the mixed layer clays. Typical examplesof specific clays belonging to these classes are the smectices, kaolins,illites, chlorites, attapulgites and mixed layer clays. Smectites, forexample, include montmorillonite, bentonite, pyrophyllite, hectorite,saponite, sauconite, nontronite, talc, beidellite, volchonskoite andvermiculite. Kaolins include kaolinite, dickite, nacrite, antigorite,anauxite, halloysite, indellite and chrysotile. Illites includebravaisite, muscovite, paragonite, phlogopite and biotite. Chloritesinclude corrensite, penninite, donbassite, sudoite, pennine andclinochlore. Attapulgites include sepiolite and polygorskyte. Mixedlayer clays include allevardite and vermiculitebiotite. Variants andisomorphic substitutions of these layered clay minerals offer uniqueapplications.

The layered clay minerals of the present invention may be eithernaturally occurring or synthetic. Example of suitable nanotechnologyagents include natural or synthetic hectorites, montmorillonites andbentonites. Other examples include hectorites clays. Commerciallyavailable, and typical sources of commercial hectorites are theLAPONITEs from Southern Clay Products, Inc., U.S.A; Veegum Pro andVeegum F from R. T. Vanderbilt, U.S.A.; and the Barasyms, Macaloids andPropaloids from Baroid Division, National Read Comp., U.S.A.

The inorganic metal oxides of the present invention may be silica- oralumina-based nanotechnology agents that are naturally occurring orsynthetic. Aluminum can be found in many naturally occurring sources,such as kaolinite and bauxite. The naturally occurring sources ofalumina are processed by the Hall process or the Bayer process to yieldthe desired alumina type required. Various forms of alumina arecommercially available in the form of Gibbsite, Diaspore, and Boehmitefrom manufactures such as Condea, Inc.

Boehmite alumina is a water dispersible, inorganic metal oxide having amean particle size distribution of about 25 nanometers. Such product iscommercially available, for example under the trade name Disperal P2™.

Natural clay minerals typically exist as layered silicate minerals andless frequently as amorphous minerals. A layered silicate mineral hasSiO₄ tetrahedral sheets arranged into a two-dimensional networkstructure. A 2:1 type layered silicate mineral has a laminated structureof several to several tens of silicate sheets having a three layeredstructure in which a magnesium octahedral sheet or an aluminumoctahedral sheet is sandwiched between two sheets of silica tetrahedralsheets.

A sheet of an expandable layer silicate has a negative electric charge,and the electric charge is neutralized by the existence of alkali metalcations and/or alkaline earth metal cations. Smectite or expandable micacan be dispersed in water to form a sol with thixotropic properties.Further, a complex variant of the smectite type clay can be formed bythe reaction with various cationic organic or inorganic compounds. As anexample of such an organic complex, an organophilic clay in which adimethyldioctadecyl ammonium ion(a quaternary ammonium ion) isintroduced by cation exchange and has been industrially produced andused as a gellant of a coating.

With appropriate process control, the processes for the production ofsynthetic nanoscale powders (i.e. synthetic clays) does indeed yieldprimary particles, which are nanoscale. However, the particles are notusually present in the form of discrete particles, but insteadpredominantly assume the form of agglomerates due to consolidation ofthe primary particles. Such agglomerates may reach diameters of severalthousand nanometers, such that the desired characteristics associatedwith the nanoscale nature of the particles cannot be achieved. Theparticles may be deagglomerated, for example, by grinding as describedin EP-A 637,616 or by dispersion in a suitable carrier medium, such aswater or water/alcohol and mixtures thereof.

The production of nanoscale powders such as layered hydrous silicate,layered hydrous aluminum silicate, fluorosilicate, mica-montmorillonite,hydrotalcite, lithium magnesium silicate and lithium magnesiumfluorosilicate are common. An example of a substituted variant oflithium magnesium silicate is where the hydroxyl group is partiallysubstituted with fluorine. Lithium and magnesium may also be partiallysubstituted by aluminum. In fact, the lithium magnesium silicate may beisomorphically substituted by any member selected from the groupconsisting of magnesium, aluminum, lithium, iron, chromium, zinc andmixtures thereof.

Synthetic hectorite was first synthesized in the early 1960's and is nowcommercially marketed under the trade name LAPONITE™ by Southern ClayProducts, Inc. There are many grades or variants and isomorphoussubstitutions of LAPONITE™ marketed. Examples of commercial hectoritesare LAPONITE B™, LAPONITE S™, LAPONITE XLS™, LAPONITE RD™ and LAPONITERDS™. One embodiment of this invention uses LAPONITE XLS™ having thefollowing characteristics: analysis (dry basis) SiO₂ 59.8%, MgO 27.2%,Na₂ O 4.4%, Li₂ O 0.8%, structural H₂ O 7.8%, with the addition oftetrasodium pyrophosphate (6%); specific gravity 2.53; bulk density 1.0.

Synthetic hectorites, such as LAPONITE RD™, do not contain any fluorine.An isomorphous substitution of the hydroxyl group with fluorine willproduce synthetic clays referred to as sodium magnesium lithiumfluorosilicates. These sodium magnesium lithium fluorosilicates,marketed as LAPONITE™ and LAPONITE S™, may contain fluoride ions of upto approximately 10% by weight. It should be understood that thefluoride ion content useful in the compositions described herein cancomprise any whole or decimal numeric percentage between 0 and 10 ormore. LAPONITE B™, a sodium magnesium lithium fluorosilicate, has aflat, circular plate-like shape, and may have a diameter with a meanparticle size, depending on fluoride ion content, that is any number (ornarrower set of numbers) that is within the range of between about25–100 nanometers. For example, in one non-limiting embodiment, LAPONITEB™ may be between about 25–40 nanometers in diameter and about 1nanometer in thickness. Another variant, called LAPONITE S™, containsabout 6% of tetrasodium pyrophosphate as an additive. In some instances,LAPONITE B™ by itself is believed, without wishing to be bound to anyparticular theory, to be capable of providing a more uniform coating(that is, more continuous, i.e., less openings in the way the coatingforms after drying), and can provide a more substantive (or durable)coating than some of the other grades of LAPONITE™ by themselves (suchas LAPONITE RD™). The coating preferably forms at least one layer ofnanotechnology agents on the surface which has been coated, and issubstantially uniform.

Inorganic metal oxides generally fall within two groups-photoactive andnon-photoactive nanotechnology agents. General examples of photoactivemetal oxide nanotechnology agents include zinc oxide and titanium oxide.Photoactive metal oxide nanotechnology agents require photoactivationfrom either visible light (e.g. zinc oxide) or from UV light (TiO₂).Zinc oxide coatings have generally been used as anti-microbial agents oras anti-fouling agents.

Non-photoactive metal oxide nanotechnology agents do not use UV orvisible light to produce the desired effects. Examples ofnon-photoactive metal oxide nanotechnology agents include, but are notlimited to: silica and alumina nanotechnology agents, and mixed metaloxide nanotechnology agents including, but not limited to smectites,saponites, and hydrotalcite.

A lotion composition may comprise oils and/or emollients and/or waxesand/or immobilizing agents.

The lotion compositions may be heterogeneous. They may contain solids,gel structures, polymeric material, a multiplicity of phases (such asoily and water phase) and/or emulsified components. It may be difficultto determine precisely the melting temperature of the lotioncomposition, i.e. difficult to determine the temperature of transitionbetween the liquid form, the quasi-liquid from, the quasi-solid form andthe solid form. The terms melting temperature, melting point, transitionpoint and transition temperature are used interchangeably in thisdocument and have the same meaning.

The lotion compositions may be semi-solid, of high viscosity so they donot substantially flow without activation during the life of the productor gel structures.

The lotion compositions may be shear thinning and/or they may stronglychange their viscosity around skin temperature to allow for transfer andeasy spreading on a user's skin.

The lotion compositions may be in the form of emulsions and/ordispersions.

A nonlimiting example of a suitable lotion composition of the presentinvention comprises a chemical softening agent, such as an emollient,that softens, soothes, supples, coats, lubricates, or moisturizes theskin. The lotion composition may sooth, moisturize, and/or lubricate auser's skin.

The lotion composition may comprise an oil and/or an emollient.Nonlimiting examples of suitable oils and/or emollients include glycols(such as propylene glycol and/or glycerine), polyglycols (such astriethylene glycol), petrolatum, fatty acids, fatty alcohols, fattyalcohol ethoxylates, fatty alcohol esters and fatty alcohol ethers,fatty acid ethoxylates, fatty acid amides and fatty acid esters,hydrocarbon oils (such as mineral oil), squalane, fluorinatedemollients, silicone oil (such as dimethicone) and mixtures thereof.

Nonlimiting examples of emollients useful in the present invention canbe petroleum-based, fatty acid ester type, alkyl ethoxylate type, ormixtures of these materials. Suitable petroleum-based emollients includethose hydrocarbons, or mixtures of hydrocarbons, having chain lengths offrom 16 to 32 carbon atoms. Petroleum based hydrocarbons having thesechain lengths include petrolatum (also known as “mineral wax,”“petroleum jelly” and “mineral jelly”). Petrolatum usually refers tomore viscous mixtures of hydrocarbons having from 16 to 32 carbon atoms.A suitable Petrolatum is available from Witco, Corp., Greenwich, Conn.as White Protopet® 1 S.

Suitable fatty acid ester emollients include those derived from longchain C₁₂–C₂₈ fatty acids, such as C₁₆–C₂₂ saturated fatty acids, andshort chain C₁–C₈ monohydric alcohols, such as C₁–C₃ monohydricalcohols. Nonlimiting examples of suitable fatty acid ester emollientsinclude methyl palmitate, methyl stearate, isopropyl laurate, isopropylmyristate, isopropyl palmitate, and ethylhexyl palmitate. Suitable fattyacid ester emollients can also be derived from esters of longer chainfatty alcohols (C₁₂–C₂₈, such as C₁₂–C₁₆) and shorter chain fatty acidse.g., lactic acid, such as lauryl lactate and cetyl lactate.

Suitable fatty acid ester type emollients include those derived fromC₁₂–C₂₈ fatty acids, such as C₁₆–C₂₂ saturated fatty acids, and shortchain (C₁–C₈ and/or C₁–C₃) monohydric alcohols. Representative examplesof such esters include methyl palmitate, methyl stearate, isopropyllaurate, isopropyl myristate, isopropyl palmitate, and ethylhexylpalmitate. Suitable fatty acid ester emollients can also be derived fromesters of longer chain fatty alcohols (C₁₂–C₂₈ and/or C₁₂–C₁₆) andshorter chain fatty acids e.g., lactic acid, such as lauryl lactate andcetyl lactate.

Suitable alkyl ethoxylate type emollients include C₁₂–C₁₈ fatty alcoholethoxylates having an average of from 3 to 30 oxyethylene units, such asfrom about 4 to about 23. Nonlimiting examples of such alkyl ethoxylatesinclude laureth-3 (a lauryl ethoxylate having an average of 3oxyethylene units), laureth-23 (a lauryl ethoxylate having an average of23 oxyethylene units), ceteth-10 (acetyl ethoxylate having an average of10 oxyethylene units), steareth-2 (a stearyl ethoxylate having anaverage of 2 oxyethylene units) and steareth-10 (a stearyl ethoxylatehaving an average of 10 oxyethylene units). These alkyl ethoxylateemollients are typically used in combination with the petroleum-basedemollients, such as petrolatum, at a weight ratio of alkyl ethoxylateemollient to petroleum-based emollient of from about 1:1 to about 1:3,preferably from about 1:1.5 to about 1:2.5.

The lotion compositions of the present invention may include an“immobilizing agent”, so-called because they are believed to act toprevent migration of the emollient so that it can remain primarily onthe surface of the fibrous structure to which it is applied so that itmay deliver maximum softening benefit as well as be available fortransferability to the user's skin.

Immobilizing agents include agents that are may prevent migration of theemollient into the fibrous structure such that the emollient remainprimarily on the surface of the fibrous structure and/or sanitary tissueproduct and/or on the surface treating composition on a surface of thefibrous structure and/or sanitary tissue product and facilitate transferof the lotion composition to a user's skin. Immobilizing agents mayfunction as viscosity increasing agents and/or gelling agents.

Nonlimiting examples of suitable immobilizing agents include waxes (suchas ceresin wax, ozokerite, microcrystalline wax, petroleum waxes, fishertropsh waxes, silicone waxes, paraffin waxes), fatty alcohols (such ascetyl, cetaryl, cetearyl and/or stearyl alcohol), fatty acids and theirsalts (such as metal salts of stearic acid), mono and polyhydroxy fattyacid esters, mono and polyhydroxy fatty acid amides, silica and silicaderivatives, gelling agents, thickeners and mixtures thereof.

One or more skin benefit agents may be included in the substrate.Nonlimiting examples of skin benefit agents include zinc oxide,vitamins, such as Vitamin B3 and/or Vitamin E, sucrose esters of fattyacids, such as Sefose 1618S (commercially available from Procter &Gamble Chemicals), antiviral agents, anti-inflammatory compounds, lipid,inorganic anions, inorganic cations, protease inhibitors, sequestrationagents, chamomile extracts, aloe vera, calendula officinalis, alphabisalbolol, Vitamin E acetate and mixtures thereof.

Nonlimiting examples of suitable skin benefit agents include fats, fattyacids, fatty acid esters, fatty alcohols, triglycerides, phospholipids,mineral oils, essential oils, sterols, sterol esters, emollients, waxes,humectants and combinations thereof.

The skin benefit agent may be alone, included in a lotion compositionand/or included in a surface treating composition. A commerciallyavailable lotion composition comprising a skin benefit agent isVaseline® Intensive Care Lotion (Chesebrough-Pond's, Inc.).

Nonlimiting Example of Present Invention

Samples to be evaluated are obtained. Participants for the study areselected. Participants were excluded from the study if: 1) they werecurrently participating in any other clinical study, 2) they hadparticipated in any type of research study involving the forearms withinthe previous twenty-one days, 3) they had allergies to soap, detergent,perfume, cosmetics, and/or toiletries, 4) they were takinganti-inflammatory corticosteriods or other medications that mayinterfere with test results, 5) they had had eczema or psoriasis withinthe past six months, 6) they had been diagnosed with skin cancer withinthe previous twelve months, 7) they were pregnant or lactating, or 8)they had cuts, scratches, rashes or any condition on their innerforearms that may prevent a clear assessment of their skin.

Participants are given an Olay® Sensitive Skin Care Bar for all bathingand showering needs to be used beginning with their enrollment into thestudy and until their participation in the study is complete. Instructparticipants to avoid scrubbing the inner forearm areas and allow thesoap and water to flow over the areas without washing. In addition, theyare required to refrain from using lotions, creams, ointments, oilsand/or moisturizers on the forearm areas.

Two to three test sites are identified and demarcated on each volarsurface of the forearm. Test sites are measured 4 cm×4 cm, and were 4 cmapart. Each site is treated with a different sample. The samples arerandomized, and the technician conducting the test is not aware of thetest sample identity. Treatments at the test sites include a 24-hoccluded patch of 0.3 ml of a solution of SLS, and wiping (rubbing) thetest samples in a back and forth motion a specified number of times.

For the sample wipes, each sample is folded up to five times, and wiped10 times in a back and forth movement (20 passes). The test sample isthen refolded and the wiping repeated with a fresh area of the sample.New samples are used, as needed until the total number of back and forthwipes is completed. The SLS is patched using a Webril® patch(Professional Medical Products Company) covered by an occlusive,hypoallergenic tape (Blenderm®, 3M Company).

Scoring of the test sites is done at baseline (prior to any treatment)and before and after either patching with SLS or wiping with the testsamples. When SLS patching is conducted, the patches are removed 30–60minutes before grading. In all studies, visual scoring is conducted byexpert graders under a 100 watt incandescent daylight bulb. If a testsite exhibits an erythema grade of “2” or higher, that test sitereceives no further treatment.

EXAMPLES Example 1 Facial Tissues Comprising Lotion

Test sites on the flexor surfaces of the forearms of 19 subjects(participants) were wiped with the lotion-containing samples (tissues)on day 1 using a total of 200 wipes (400 passes) in order to pretreatthe portion of skin with lotion. This was followed by a 24-h occlusivepatch with 0.25% SLS (sodium lauryl sulfate). Visual scoring of erythemaand dryness was conducted. Scoring of the test sites was done prior toany treatment, immediately after the sample wipes (post sample wipes),30 minutes after removal of the SLS patch (post-SLS patch, 24-h postwipe), and 24 hours after removal of the SLS patch (post-SLS patch, 48-hpost wipe). The group mean scores (+/−standard error) for dryness (a)and erythema (b) were determined for each scoring timepoint.Post-baseline average treatment comparisons were performed usinganalysis of variance (“ANOVA”). All other treatment comparisons wereperformed using the stratified Cochran Mantel Haenszel (“CMH”) test. ForSample 1, the concentration of lotion on the sample was 0.668 mg/cm².Since Sample 2 is a currently marketed competitor's product, the lotionconcentration is unknown. As shown in FIG. 1:

Sample 1 is statistically lower than tissue Sample 2 (with lotion)(p<0.05).

Example 2 Facial tissues comprising lotion

Test sites on the flexor surfaces of the forearms of 18 subjects werepretreated by 24-h patch with 0.25% SLS. After patch removal, test siteswere wiped with the test samples (tissues) using a total of 200 wipes(400 passes). Visual scoring of erythema and dryness of the test siteswas done prior to any treatment, 30 minutes after removal of the SLSpatch, immediately after the sample wipes (post sample wipe), and at 24and 48 hours after the sample wipes (post-sample wipe, 24-h, andpost-sample wipe, 48-h). The change from post-SLS baseline wasdetermined for each subject, then the average over all subjects wascalculated. The post-baseline average was calculated using the averageof all post-baseline visits for each subject, then calculating theaverage over all subjects. Treatment comparisons for erythema at 24-h,48-h, and the change in post-baseline average were performed using ANOVAon ranks. For Sample 1, the concentration of lotion was 0.668 mg/cm².Since Sample 2 is a currently marketed competitor's product, the lotionconcentration is unknown. As shown in FIG. 2:

Sample 1 is statistically lower than Sample 2 (without lotion) (p<0.05).

Sample 2 is statistically lower than Sample 1 (without lotion) (p<0.05).

Sample 2 is statistically lower than Sample 1 (without lotion) (p<0.05).

Sample 1 is statistically lower than Sample 2 (with lotion) (p<0.05).

Example 3 Facial Tissues Comprising Lotion

Test sites on the flexor surfaces of the forearms of 15–18 subjects werepretreated by 24-h patch with 0.25% SLS. After patch removal, test siteswere wiped with the test samples using a total of 200 wipes (400passes). Visual scoring of erythema and dryness of the test sites wasdone prior to any treatment, 30 minutes after removal of the SLS patch,immediately after the sample wipes, and at 24, 48 and 72 hours after thesample wipes. The change from post-SLS baseline was determined for eachsubject, then the average over all subjects was calculated. Thepost-baseline average was calculated using the average of allpost-baseline visits for each subject, then calculating the average overall subjects. Erythema post-baseline average comparisons were performedusing ANOVA. All other treatment comparisons were performed using ANOVAon ranks. For Sample 1, the concentration of lotion was 0.668 mg/cm² andthe concentration of lotion for Sample 2 was 0.815 mg/cm². Both sampleshad 3000 ppm of silicone on them. As shown in FIG. 3:

Sample 1 is statistically lower than Sample 2 (without silicone)(p<0.05).

Sample 1 is statistically lower than Sample 2 (without silicone)(p<0.05).

Sample 2 is statistically lower than tissue Sample 1 (without silicone)(p<0.05).

Example 4 Feminine Pads Comprising Lotion

Test sites on the flexor surfaces of the forearms of 19 subjects(participants) were wiped with the lotion-containing samples (femininepads). On day 1 using a total of 120 wipes in order to pretreat theportion of skin with lotion. Different test products were used. This wasfollowed by a 24-h occlusive patch with 0.25% SLS (sodium laurylsulfate). Visual scoring of erythema and dryness was conducted. Scoringof the test sites was done prior to any treatment, immediately after thesample wipes (post sample wipes), 30 minutes after removal of the SLSpatch (post-SLS patch, 24-h post wipe), and 24 hours after removal ofthe SLS patch (post-SLS patch, 48-h post wipe). The group mean scores(+/−standard error) for dryness (a) and erythema (b) were determined foreach scoring timepoint. Objective instrumental measurements were takenusing but not restricted to DermaLab® evaporimeter instrument will beused to assess transepidermal water loss (TEWL) at the test sitesincluding the upper arm control site following all visual gradingevaluations.

Post-baseline average treatment comparisons were performed usinganalysis of variance (“ANOVA”). All other treatment comparisons wereperformed using the stratified Cochran Mantel Haenszel (“CMH”) test.

For all of Examples 1–3, the post-baseline average was calculated usingthe average of all post-baseline visits for each subject, thencalculating the average over all subjects. If there were missing visitsfor a subject, that subject was not included in the calculation of thepost-baseline average.

Additionally, in those experiments where SLS patching occurred prior totreatment with the lotion, the results are presented as the change ingroup mean. The change in group mean was calculated by determining thechange from post-SLS baseline for each subject, then calculating theaverage over all subjects. In some cases, not all test subjectscompleted the entire test. In these instances, the scores recorded forthe dropped subjects were removed from the calculation of the change ingroup mean for that timepoint.

All p-values were unadjusted for multiple comparisons.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this written document conflicts with any meaningor definition of the term in a document incorporated by reference, themeaning or definition assigned to the term in this written documentshall govern.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A method for assessing irritation of skin, the method comprising thesteps of: a irritating a portion of skin of a test subject by a firstmode; and b. irritating the portion of skin by a second mode differentfrom the first mode, wherein the second mode comprises rubbing a testsample substrate on the portion of skin; c. objectively assessingerythema and/or dryness of the portion of skin after the irritatingsteps.
 2. The method according to claim 1 wherein the first mode isselected from the group consisting of: chemical irritation, physicalirritation and mixtures thereof.
 3. The method according to claim 2wherein the first mode is chemical irritation.
 4. The method accordingto claim 2 wherein the first mode is physical irritation.
 5. The methodaccording to claim 1 wherein the step of irritating a portion of skin bya first mode comprises contacting the portion of skin with a skinirritant agent.
 6. The method according to claim 5 wherein the skinirritant agent is selected from the group consisting of: sodium laurylsulfate, sodium laureth sulfate and mixtures thereof.
 7. The methodaccording to claim 1 wherein the step of irritating a portion of skin bya first mode comprises tape stripping the portion of skin.
 8. The methodaccording to claim 1 wherein the step of irritating a portion of skin bya first mode comprises occluding the portion of skin.
 9. The methodaccording to claim 1 wherein the substrate is a fibrous structure. 10.The method according to claim 9 wherein the fibrous structure is asanitary tissue product.
 11. The method according to claim 1 wherein thesubstrate comprises a fibrous structure comprising a lotion.
 12. Themethod according to claim 1 wherein the substrate comprises an additiveselected from the group consisting of: chemical softening agents, dyes,colorants, surfactants, absorbents, permanent wet strength agents,temporary wet strength agents, antiviral agents, oils, nanotechnologyagents, lotion compositions, skin benefits agents, skin healants,perfumes, especially long lasting and/or enduring perfumes,antibacterial agents, botanical agents, disinfectants, pharmaceuticalagents, film formers, deodorants, opacifiers, astringents, solvents,cooling sensate agents such as camphor, thymol and menthol, andpreservatives.
 13. The method according to claim 12 wherein the chemicalsoftening agent is selected from the group consisting of: silicones,quaternary ammonium compounds, petrolatum, oils and mixtures thereof.14. The method according to claim 13 wherein the silicones compriseaminosilicones.
 15. The method according to claim 12 wherein thesubstrate comprises an antiviral agent.
 16. The method according toclaim 1 wherein the step of objectively assessing erythema and/ordryness comprises assessing erythema and/or dryness by an expert grader.17. The method according to claim 1 wherein the step of objectivelyassessing erythema and/or dryness comprises assessing objectiveinstrumental measurements of erythema and/or dryness.